1. Field of the Invention
This invention relates to the new chemical compound, 1,5-diaminoheptanol-6, to a process for its preparation from L-lysine and to its use as chain lengthening agent for the preparation of polyurethane polyureas by the isocyanate polyaddition process.
2. Description of the Prior Art
It is known in the prior art to subject dissolved polyurethane polyurea resins of a linear structure to a cross-linking reaction on a substrate using melamine- or urea-formaldehyde resins. The acceptor groups for the methylol groups are the NH groups from the urethane and urea groups of the polymer chain. The disadvantage of this cross-linking reaction is that it generally requires high temperatures in the region of about 150.degree. to 170.degree. C. for sufficient cross-linking. Even though the incorporation of hydrazine into the polymer chain or into amide groups in side positions (according to DE-A 2,457,387 or DE-A 3,345,071) has improved the stoving conditions, further improvements are necessary.
Accordingly, it is an object of the present invention to provide a chain-extender which may be used in the production of polyurethane polyureas such that they may be cross-linked e.g. with formaldehyde resins under very mild conditions. It is an additional object of the present invention to prepare cross-linked coatings or films which are chemically resistant on substrates such as metals, plastics, paper or wood.
It has been discovered that these objectives may be achieved by using the chain extender set forth hereinafter for the production of polyurethane polyureas.